Components and method for improved impression making

ABSTRACT

The invention relates to components for an improved system for pick-up impression making at a dental implantation site, including an abutment, an abutment replica and an impression coping. The invention also relates to a series of abutments and to a set comprising an abutment and an impression coping. The impression coping has a through passage extending from a coronal end to an apical end of the impression coping and includes an abutment surrounding region for surrounding the abutment. The abutment surrounding region has a coronal end, an apical end and an inner wall. The inner wall includes at least one abutment contact surface for contact with the abutment, and at least one space forming surface for being spaced apart from the abutment in order to provide a space between the space forming surface and the abutment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to components for an improved system for pick-upimpression making at a dental implantation site, comprising animpression coping and an abutment replica. The invention also relates toa set comprising an abutment and an impression coping and to a methodfor impression making.

2. Description of Related Art

Dental implant systems are widely used for replacing damaged or lostnatural teeth. In such systems, an implant is placed in the jaw of apatient in order to replace the natural tooth root. An abutmentstructure comprising one or several parts may then attached to theimplant in order to build up a core for the part of the prosthetic toothprotruding from the bone tissue, through the soft gingival tissue andinto the mouth of the patient. On said abutment, the prosthesis or crownmay finally be seated.

The final prosthesis must be sized and configured so as to naturally fitwith the remaining teeth of the patient, both for functionality andaesthetics. To this end, a dental technician needs to try out a properprosthesis for the individual patient, using a model of the jaw of thepatient, said model including the implant and possibly an abutmentstructure. To provide such a model, so-called master cast modellingtechniques are used.

One category of such modelling techniques is the so-called “pick-up”method. A pick-up method could be described by the following subsequentsteps:

-   -   An impression cap is placed on the implant and/or the abutment.    -   An impression material is applied to the jaw, such that said        impression cap is embedded in the impression material.    -   The impression material is removed from the jaw, bringing along        the impression cap still being embedded in the impression        material. The impression material now has the inverse form of        the jaw with the impression cap at the site of the        implant/abutment.    -   A replica replicating the shape of the implant and/or abutment        is inserted into the embedded impression cap, in the same manner        as the original implant and/or abutment was connected to the        impression cap.    -   A molding material is poured into the inverse form of the jaw        made out of the impression material and around the replica and        let to harden.    -   The impression material is removed from the hardened molding        material, said molding material now forming a true, or        non-inverse model of the jaw with the replica replacing the        original implant/abutment.

In the following, reference will be made to some prior art documentsdescribing pick-up methods or components to be used therewith.

U.S. Pat. No. 6,068,478 (Grande et al.) discloses an impression systemincluding an impression cap for transferring an end, protruding from ahuman tissue structure, of an implant which is fitted in the human body,including possible superstructures, to a master cast. The outwardlydirected implant end has an undercut contour on its outside, and theimpression cap has a geometry which complements the undercut contour andengages therein. The undercut contour is formed either by an implantgeometry tapering in a trumpet shape towards the implant bed, or by arecess near the implant end.

In said U.S. Pat. No. 6,068,478 (Grande et al.), a superstructure partis described to be screwed into the implant such that an abutment of thesuperstructure is projecting above the implant shoulder. For taking animpression of the mouth situation to a finished master cast, a slidesleeve is first of all pushed onto the conical superstructure. Then, animpression cap is pushed over the slide sleeve. At the very bottom, theimpression cap has a cap shoulder, which is complementary to the implantshoulder. On the outside, the cap shoulder is surrounded by an elasticsnap element directed inwards, so that it can snap over the implantshoulder and releasably grip an undercut contour on the implant head. Animpression tray filled with impression compound is now pressed onto theimplantation site. After withdrawing the impression tray, the impressioncap and the slide sleeve remain embedded in the impression compound, andthe impression is obtained. An analogous manipulation implant having ashape corresponding to the conical superstructure is now pushed into theslide sleeve. Finally, a manipulation shoulder sleeve, having amanipulation shoulder corresponding to the implant shoulder is pushedover the manipulation implant until the manipulation shoulder is held bythe snap element of the impression cap. Modelling compound is lastlypoured onto the impression and the master cast is obtained.

In said U.S. Pat. No. 6,068,478 (Grande et al.), another impressionmethod is used if another type of superstructure, for example an angledsuperstructure is attached to an implant. In this case, an impressioncylinder is screwed onto the superstructure and a laterally openimpression cap is pushed onto the superstructure such that is grabs theimplant shoulder. The impression is taken using the impression trayfilled with impression compound, which impression is obtained afterwithdrawing the impression tray, and in which the impression cap and ahollow space according to the impression cylinder and the conicalsuperstructure remain behind. In the next step, the impression cylinderis pushed into its hollow space and the manipulation shoulder sleeve isattached, and modelling compound is then filled through the manipulationshoulder sleeve so that the whole hollow space is filled up. Modellingcompound is now poured onto the impression and, after removing theimpression tray in which the impression cylinder remains, the finishedmater cast is obtained.

It is further mentioned that the slide sleeve might be omitted if thehollow space remaining in the impression cap, and left by the selectedabutment inside the impression cap, is filled with impression compound.Also, the slide sleeve and the impression cap may be combined anddesigned as one piece.

U.S. Pat. No. 6,159,010 (Rogers et al.) discloses a dental coping forplacement over an abutment post that is attached to and protruding abovea dental implant. The coping includes a base portion having aninternally tapered surface for mating with a support surface of theimplant. A wall extends away from the base portion for enveloping theabutment post. The wall includes at least one aperture for allowing waxmaterial to pass therethrough when taking an impression of theimplantation site.

U.S. Pat. No. 5,688,123 (Meiers et al.) discloses a transfer cap fordental implants that is to be used when taking an impression for forminga master cast model. This transfer cap is adapted in form and size tothe built-up part or abutment of the implant and carries one or moreresilient flaps extending over the shoulders of a conical area of thebuilt-up part.

WO 99/29255 (Morgan) discloses an abutment analogue having a headportion being formed with retention means such as an annular groove.

EP 0 190 670 (Lustig) discloses a prefabricated abutment that may beused in combination with a prefabricated sleeve-like coping which istelescopically mated to the post.

An object of this invention is to provide components for a system forimproved function when using pick-up impression methods, and a methodusing said components.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided animpression coping for pick-up impression making of a dental abutmentattached to a dental implant, said impression coping having a throughpassage from an apical and to a coronal end of the impression coping.The impression coping comprises an abutment surrounding region forsurrounding said abutment, said abutment surrounding region having anapical end and a coronal end and an inner wall, comprising at least oneabutment contact surface for contact with said abutment, and at leastone space forming surface for being spaced apart from said abutment inorder to provide a space between said space forming surface and saidabutment.

The term “coronal” is here and throughout this application used toindicate a direction towards a head end or trailing end of the componentdiscussed. For example, in a situation where an abutment is connected toan implant, the coronal direction would be a direction towards the partof the abutment being directed away from the implant. Likewise, the term“apical” indicates a direction towards an insertion end of thecomponent. For an abutment connected to an implant, the apical directionwould be a direction towards the implant. Thus, apical and coronal areopposite directions.

However, if parts of a component or a system are angulated in relationto each other, the apical and coronal directions of the different parts,respectively, may not be coinciding. For example, this would be the casefor an abutment where the component support region of an abutment isangled in relation to the implant contacting region, a so called angledabutment. Herein, when discussing the apical direction of the componentsupport region, a direction towards the maximum diameter of thecomponent support region is referred to. The coronal direction of acomponent support region is a direction away from said maximum diameter,towards a free end of the component support region.

Preferably, the impression coping is having a through passage extendingfrom a coronal end to an apical end of the impression coping. This isadvantageous since impression material may then be introduced throughthe coronal end into the impression coping, thus increasing the fixationof the impression coping in the impression material. Impression materialintroduced into the impression coping will contact part of the abutment,and thus provide an open space replicating said abutment part. This openspace may be used for guiding the later introduction of an abutmentreplica, or as will be described in the detailed part of thedescription, as a form for forming a model of a customised abutment.

Further, impression material may be introduced in said space betweensaid space forming surfaces and said abutment. However, there are alsoabutment contact surfaces, that contacts the abutment thus providing astable contact surface.

When taking an impression of a standard abutment, the abutment contactsurfaces will contact the standard abutment. Impression material mayoptionally be introduced into the spaces formed by the space formingsurfaces, but this is not necessary. The abutment contact surfaces willnamely normally provide enough surface to guide the later insertion ofan abutment replica into exactly the same position as the abutment hadinside the impression coping.

However, when taking an impression of a modified abutment, all of theabutment contact surfaces will probably not be in contact with themodified abutment. At least a portion of the abutment contact surfaceswill most likely not contact the customised abutment, due to themodified shape thereof. In this case a composite space is formed betweenthe abutment and the inner wall of the impression coping, said compositespace being composed by a space created between the abutment contactsurface and the modified abutment and said space between said spaceforming surface and said abutment. Impression material may be introducedinto the impression coping and into the composite space formed betweensaid impression coping and the modified abutment. Thus, when removedfrom the abutment, the impression material together with the impressioncoping will form an empty space having an inner “modified” shapecorresponding to the shape of the modified abutment, said inner shapebeing subsequently used for molding a model of said modified abutment.

Preferably, said space forming surface may be provided with a vent forpassage air from said composite space. Thus, when impression material isintroduced into said composite space, air may flow through the spaceformed between said space forming surface and said abutment out throughthe vent, whereby air bubbles are avoided and proper introduction ofimpression material is ensured. The space forming surface thus providesan air duct for air evacuation from said composite space.

The vent may be provided by an opening in the space forming surface orpossibly by a perforation or other suitable vent means.

Naturally, the abutment may alternatively be modified such that all ofthe abutment contact surface is still in contact with the modifiedabutment, and the composite space is related only to the space formingsurfaces. The extent to which said composite space needs filling withimpression material is dependent on the modification made of theabutment. However, complete filling may normally be ensured by havingimpression material filled into the entire composite space and flowingout of said vent.

Advantageously, at least one abutment contact surface may be taperinginwardly in a coronal direction. This is particularly useful when theimpression coping is to be seated on an abutment having a tapered outershape.

The impression coping is thus useful both for taking impressions of astandard abutment and of a modified standard abutment. This providesadvantages over prior art, where different components are often used forstandard and customised situations.

In a first variant of said impression coping, the abutment surroundingregion of the impression coping comprises a shoulder contacting portionhaving an inner wall and a post surrounding portion extending coronallyfrom said shoulder contacting portion and presenting an inner wallforming an angle larger than 180° with said inner wall of said shouldercontacting portion.

The shoulder contacting portion is intended to contact a shoulderportion of a corresponding abutment. Accordingly, the projection of anormal to the outer surface of said shoulder contacting portion onto alongitudinal axis of the component surrounding region would extend inthe apical direction.

The post surrounding portion may have an inner wall having variousshapes. It may be formed such that the entire inner wall contacts a postportion of an abutment. However, it may also be formed so as to contactthe post portion of an abutment only with a part of said inner wall.Some such embodiments will be described below.

Further, the shoulder contacting portion is useful for increasingcontact and stability in the interaction with said abutment. This isparticularly important as the impression coping will be used in pick-upimpression methods, where it will first be attached to an abutment beingfixed to an implant, thereafter embedded in impression material andremoved from the abutment together with said impression material, andfinally an abutment replica will be inserted into said impressioncoping. For succeeding with this method, both the abutment and theabutment replica should be securable in the impression coping with greataccuracy, to which said shoulder contacting portion contributes.

Also, the combination of a shoulder contacting portion and postcontacting surfaces provides a possibility of ensuring that theimpression coping is correctly placed on the abutment. In some prior artsystems there are provided impression caps having only a shouldercontacting portion and a post surrounding portion with no abutmentcontact surfaces. Such prior impression caps risk however beingincorrectly placed on the abutment.

According to an embodiment of said first variant of the first aspect ofthe invention, the impression coping is further provided with releasableabutment engagement means being provided apically of at least one spaceforming surface. Preferably, said abutment engagement means are providedat the post contacting portion, at a position being closer to theshoulder contacting portion than to the coronal end of the abutmentsurrounding region.

In said embodiment of the impression coping, the placement of theabutment engagement means on the inner wall of a post contacting portionextending from a shoulder contacting portion results in a position ofthe locking means where the diameter of the abutment on which theimpression coping is to be seated is relatively small, as compared tothe diameter at a shoulder portion of the abutment. Thus, this placementof the locking means allow more construction variations of the lockingmeans to be used without having to increase the outer diameter of theimpression coping at the locking means beyond the maximum diameter ofsaid abutment.

A small outer diameter of the impression coping is advantageous. Whenhaving a large diameter, the mucosa surrounding the abutment or implantto which the impression cap is set must be pushed aside and risks beingdamaged. Further, a large diameter of an impression cap makes itdifficult to attach or remove the component without colliding with theteeth adjacent to the implant. Where the adjacent teeth are very closeset, the diameter of the component might even be too large for thecomponent to pass between the teeth to be set on the abutment. Howeverthe arrangement disclosed above diminishes these problems.

In prior art systems, locking means such as flaps are sometimes providedat the end of an impression cap for engagement over and around anabutment. In these constructions, the locking means will contribute toan enlarged outer diameter of the impression cap, leading to unnecessarycompression of the soft gingival tissue surrounding the abutment.Further, the placement of the locking means at the end of the impressioncaps often leads to a low attachment level of the cap down in thegingival tissue of the patient.

In other prior systems there are locking means provided close to thecoronal end of the impression cap. These systems have the disadvantagethat the abutment on which the impression cap is to be seated may not bemodified below said coronal end, if the impression cap shall still beattachable to the abutment.

The abutment engagement means may be provided at a transition betweensaid post contacting portion and said shoulder contacting portion.Further, the abutment engagement means may comprise at least oneprotrusion or indentation, such as a groove or rib, in an inner wall ofsaid abutment surrounding region.

At least one abutment contact surface may be provided with a rotationallocking means, for rotational locking of said impression coping on saiddental abutment. This feature is useful for ensuring a proper transferof the rotational direction of the abutment fixed to the implant to amaster cast model via impression making.

For enhanced attachment into the impression material, the impressioncoping may be provided with a prolongation region coronally of theabutment surrounding region. Such a prolongation region will also makethe impression coping easier to handle. Said prolongation region mayfurther be provided with retention elements for retention of theimpression coping in an impression material.

According to a second aspect of the invention, there is provided a setcomprising an abutment and an impression coping as above.

In a third aspect of the invention, there is provided an abutmentreplica, comprising a component support portion replicating thecomponent supporting region of an abutment, and an apical region havingan apical end, wherein a bore is extending from said apical end into theabutment replica, at least to a position being in level with saidcomponent support region.

This replica has the advantage that at least part of the componentsupport region may be cut off leaving a replica comprising the apicalregion and possibly a part of the support region and being provided witha through bore. This possibility is used when making a master cast of amodified abutment, which will be described in more detail in thespecified part of the description. The replica according to thisembodiment is advantageous since it may be used both for situationswhere the abutment is left in its standard appearance (in its originalstate) and for situations where the abutment is modified (in a cut-offstate).

As such, the abutment replica is particularly advantageous for usetogether with the impression coping according to the first aspect of theinvention, since also the impression coping is useful for bothsituations where the abutment is left in its standard appearance and forsituations where the abutment is modified.

In an embodiment of the abutment replica, it is further provided withabutment engagement means for connection to a dental component, whereinsaid bore extends from said apical end into the abutment replica, atleast to a position coronally of said abutment engagement means.

Thus, a part of the component support region extending coronally of thelocking means may be cut off, revealing a bore extending through theentire remaining portion of the abutment replica, which is also havingthe abutment engagement means intact.

In a fourth aspect of the invention there is provided a set comprisingan abutment having a coronal abutment end and a corresponding replicahaving a coronal replica end, said abutment being provided with amarking for optional shortening of the abutment at a first distance fromthe coronal abutment end, wherein said replica is provided with amarking at a second distance from the coronal replica end being equal toor less than said first distance.

The markings proposed according to said fourth aspect of the inventionmay be used to further increase the possibilities of simply modifyingthe system. If a shorter than standard abutment is desired, a standardabutment may be cut off at a marking. The replica used in subsequentmodel making has a correspondent marking at a distance from the coronalend of the replica equal to or less than the distance between themarking of the abutment and a coronal end of the abutment. After cuttingoff the replica at said marking there is provided a cut-off replicahaving a height being equal to or greater than the height of the cut-offabutment. In the model, a suitable prosthesis is built up on the replicaand thereafter transferred to and attached to the cut-off abutment. Thefit of the prosthesis on the abutment is ensured by the locking of theprosthesis to the abutment, which would be made in the same manner asthe locking of the prosthesis to the replica. Any open space appearingbetween the prosthesis and the abutment due to differences in heightbetween the abutment and the replica may be filled with a fillingmaterial.

In a fifth aspect of the invention there is provided a simplified methodfor making a master cast of a modified standard abutment usingcomponents suitable for taking impressions of both standard and ofmodified abutments.

Other advantages and features of the invention will appear from thefollowing description and drawings, that are to be regarded asnon-limiting examples only, in which:

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIGS. 1 a to 1 e depict a first embodiment of an abutment;

FIGS. 2 a to 2 b depict a second embodiment of an abutment;

FIG. 3 depicts a third embodiment of an abutment;

FIG. 4 depicts a fourth embodiment of an abutment;

FIGS. 5 a to 5 h depict an embodiment of a series of abutments;

FIGS. 6 a to 6 b depict an embodiment of an abutment replica;

FIGS. 7 a to 7 f depict an embodiment of an impression coping;

FIGS. 8 a to 8 b depict an embodiment of an abutment as attached to adental implant, with an embodiment of an impression coping attached tosaid abutment;

FIGS. 9 a to 9 b depict an embodiment of an abutment carrier;

FIGS. 10 a to 10 h describe a method for pick up impression making of astandard abutment; and

FIGS. 11 a to 11 h describe a method for pick up impression making of amodified standard abutment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 a is a perspective view of a first embodiment of an abutment,whereas FIGS. 1 b to 1 e are lateral views of the same abutment as inFIG. 1 a.

Turning first to FIGS. 1 a and 1 b, an abutment for connection of adental component to an implant is depicted. The abutment comprises animplant contacting region 2 for connection to a dental implant and acomponent support region 3, extending coronally of said implantcontacting region 2, for connection of a dental component thereto.

Typically, the abutment would be used for connection of a dentalprosthesis or crown to the implant. However, during the procedure ofmanufacturing the final prosthesis, the abutment would be used forconnecting other components to the implant, such as for exampleimpression copings, healing caps or a temporary prosthesis. The abutment1 may be made of a suitable material for dental components to bepermanently installed in the mouth, such as for example titanium andcertain ceramic materials, for example zirconium oxides.

The component contacting region 3 extends coronally from a maximumdiameter A (see FIG. 1 c) to a coronal end 6. The maximum diameter A ofthe component contacting region is in this case coinciding with themaximum diameter of the abutment as a whole.

Component engagement means 9 is provided at the component support region3, coronally of the maximum diameter A. The component engagement meansis structured and adapted for releasable engagement with a component bylinear displacement of said component in relation to said abutment.

The location of the component engagement means 9 coronally of themaximum diameter A result in the attachment of the component being madewhere the abutment has a relatively narrow diameter, which isadvantageous since it allows the components to be attached thereto to beconstructed with a relatively small outer diameter. A small outerdiameter makes it easier to install the component on the abutmentwithout being hindered by adjacent teeth or having to push aside anddamage the gingival tissue surrounding the abutment 1, when installed.

The component engagement means 9 is provided at a distance from saidmaximum diameter A being less than 50% of the distance between themaximum diameter A and the coronal end 6 of the abutment. Preferably,the distance should be less than 35%, and, as in the embodiment of FIGS.1 a to 1 e, the component engagement means 9 is provided at a distancebeing less than 25% of the distance between the maximum diameter A andthe coronal end 6 of the abutment.

The implant contacting region 3 comprises in this first embodiment ashoulder portion 4 and a post portion 5, extending coronally from saidshoulder portion. The outer surface 8 of the post portion 5 is formingan angle α less than 180° with the outer surface 7 of the shoulderportion. (See FIG. 1 e). The angle α formed between the outer surfaces7, 8 of the shoulder portion 4 and the post portion 5 is preferablybetween 100° and 160°, more preferred 120 to 150°, most preferred 130 to140°. In this embodiment, the angle α is 136°.

In this embodiment, the component engagement means 9 is provided at thetransition between said shoulder portion 4 and post portion 5. Thisplacement allows the major part of the post portion 5 to be modifiedwithout impairing the function of the component engagement means 9. Thecomponent engagement means 9 has the shape of a groove extending aroundpart of the circumference of the post portion 5. The groove may bedescribed as formed by a transition part 5′ of the post portion 5 havingan outer surface 8′ that forms an angle δ with the outer surface of thepost portion 5. The angle 6 is preferably in the range of 10 to 40°,more preferred 10 to 30° degrees, most preferred 12°. Favorably, acomponent may be snap locked onto the groove formed by said transitionpart 5′. The angle δ as defined above is suitable for forming such asnap lock having a preferred retaining force for securely retaining thecomponent on the abutment 1 while still enabling the component to bereleased from said abutment 1.

As related to the shoulder portion 4, the component engagement means 9is preferably provided at a distance from the shoulder portion 4 beingless than 50%, more preferred less than 30% and, as in this embodiment,less than 20% of the distance from the shoulder portion 4 to the coronalend 6 of the abutment. A component engagement means 9 may be consideredas being provided at a distance from the shoulder portion 4 being lessthan 50% the distance between the shoulder portion 4 and the coronal end6 if the component engagement means 9 is still providing a componentretaining function if a coronal portion of the abutment corresponding to50% of the distance between the shoulder portion 4 and the coronal end 6is cut off. (A corresponding definition applies to the situation wherethe location of the component engagement means 9 are related to themaximum diameter A.)

The post portion 5 is further provided with a rotational locking means15 for rotational locking of a component attached to the abutment 1. Inthis case, the rotational locking means 15 is made out of a flat part ofthe outer surface 8 of the post portion 5. However, other shapes of therotational locking means 15 may be considered. It is believed that arelatively smooth rotational lock function is preferred over more sharpand distinct locking means, since a smooth lock allows more play wheninstalling a component on the abutment.

The coronal end 6 of the post portion is optionally provided with apolygonal blind bore 19, serving as attachment for a wrench for screwingthe abutment onto an implant.

Between the component support region 3 and the implant contacting region2 there is provided an extension region 11, serving to increase theheigh with which the abutment 1 is extending over the implant wheninstalled thereto. When installed to an implant being flush with bonetissue, the extension region 11 would typically extend through gingivaltissue.

The implant contacting region 2 comprises a coronal contact portion 12and a threaded shaft 16. The implant contacting region 2 is therebyadapted for connection to an implant having a conical coronal openingand being provided with internal threads for attachment of an abutment1. The conical shape of the implant contacting region 2 and the implantopening, respectively, is particularly advantageous since it may beadapted to give rise to a conical seal when the implant and the abutmentare screwed together.

In FIG. 1 d the angles formed by the outer surfaces of differentportions of the abutment 1 with a longitudinal axis L of the abutment isindicated.

The outer surface 8 of the post portion 5 is tapering towards thecoronal direction of the abutment. This is believed to be advantageous,since it allows more lateral play in an initial stage of attaching acomponent to the abutment 1, than would be the case if the outer surface8 of the post portion 5 was parallel to the longitudinal axis L. Theangle φ formed by the outer surface 8 of the post portion 5 with thelongitudinal axis L is preferably less than 20°, more preferred lessthan 15°. In this case, the angle φ is 6°.

The above mentioned values of the angle φ are particularly suitable forproviding a post portion 5 that may cooperate with a component toprovide a retaining function between the post portion 5 and thecomponent.

Returning now to the component engagement means 9 as previouslydescribed is formed by a transition part 5′ of the post portion 5 havingan outer surface 8′ that forms an angle δ with the outer surface of thepost portion 5. The angle δ may further be described in relation to theangle φ between the longitudinal axis and the outer surface 8 of thepost portion, as advantageously being 2φ±10°. This particular choice ofangle δ enables a component attached to the abutment to be released fromsaid abutment by linear displacement with essentially the same forcethat was needed for attaching the component to said component engagementmeans. If the outer surface 8 of the post portion 5 in general forms anangle φ with said longitudinal axis L, the outer surface 8′ of thetransition part 5′ of the post portion will namely form an angle φ′ inrelation to the longitudinal axis L, φ′ being equal to φ±10°.

If using a component having an inner shape having at least some innersurfaces corresponding to the outer shape of the abutment, the forcerequired for attaching the component onto the abutment will be dependenton the angle φ formed by the outer surface 8 of the post portion 5 withsaid longitudinal axis L. The force required for removing the componentfrom the abutment will be dependent on the angle formed by the outersurface 8′ of said transition portion 5′ with said longitudinal axis L.When the angle δ is 2φ±10°, this angle will be φ±10°, meaning that theforce required for removing said component from said abutment isessentially the same as the force required for attaching said componentto said abutment 1.

The outer surface 7 of the shoulder portion 4 is likewise taperinginwardly in a coronal direction. The angle χ formed by the outer surface7 of the shoulder portion 4 with the longitudinal axis L is preferablyin the range 40 to 60°. In this case, the angle χ is 50° degrees.

The before mentioned angle α formed between the outer surface 7 of theshoulder portion 4 and the outer surface 8 of the post portion 5 wouldbe equal to (180°+φ−χ).

The outer surface 13 of the extension region 11 may be parallel to alongitudinal axis of the abutment 1 or tapering outwardly in a coronaldirection of the abutment 1. The angle φ formed by the outer surface 13of the extension region 11 with said longitudinal axis L mayadvantageously be varied so as to achieve a desired maximum diameter A.Preferably, the angle φ would be 90° to 180°.

Finally, the angle ω formed by the outer surface 14 of the coronalcontact portion 12 of the implant contacting region 2 of the abutment 1,is preferably 165° to 170°, in this case 169°.

Turning to FIG. 1 c, the maximum diameter A of the abutment 1 ispreferably in the range 3 to 7 mm, most preferred 3 to 6 mm. The maximumdiameter B of the post portion 5 is in the range 2 to 5 mm. A shelfformed by the outer surface 7 of the shoulder portion 4 would in thisembodiment have a width corresponding to half the difference betweensaid maximum diameter A of the abutment and the maximum diameter B ofthe abutment. Preferably, this width may be in the range 0.2 to 1 mm,most preferred 0.5 mm.

The axial extension of the shoulder portion 4 may be in the range10-40%, preferably 20% as compared to an axial extension of the entirecomponent support region 3. The axial extension of the extension region11 may advantageously be selected so as to achieve a desired height ofthe abutment. Normally, the extension region 11 would have an axialextension of about 10% to 50% of the axial extension of the componentsupport region 3.

Optionally, the abutment 1 may be provided with one or several markings20 indicating a level for shortening of the abutment.

FIG. 2 a is a perspective view of a second embodiment of an abutment.FIG. 2 b is a sectional view of the abutment of FIG. 2 a. Featurescorresponding to features of the above mentioned first embodiment ofFIGS. 1 a to 1 e have been provided with the same reference numerals asused in FIGS. 1 a to 1 e. Only the parts of this second embodiment thatdiffer from the first embodiment will be described below.

The second embodiment differs from the first embodiment in that theimplant contacting region 2 is not provided with a threaded shaft 16.Instead, it has a hexagonal locking structure 21 for rotational lock toan implant. The abutment 1 is further provided with a through bore 17having an internal ledge 18. A screw may be inserted in the through bore17, seating the screw head on the ledge 18, for connection of theabutment 1 to an implant. This type of abutment is particularly usefulfor single-tooth restoration situations.

FIG. 3 is a side view of a third embodiment of an abutment. Featurescorresponding to features of the above mentioned first embodiment ofFIGS. 1 a to 1 e have been provided with the same reference numerals asused in FIGS. 1 a to 1 e. Only the parts of the third embodiment thatdiffer from the first embodiment will be described below.

The third embodiment of the abutment differs from the first embodimentmainly in the height and shape of the post portion 5. The height of thepost portion 5 is shortened as compared to the first embodiment, andconstitutes approximately 75 to 80% of the axial extension of thecomponent support region 3. (This leaving about 20 to 25% of the axialextension to the shoulder portion 4). The actual length of said postportion is about 2 mm. The angle φ formed by the outer surface 8 of thepost portion 5 with the longitudinal axis L is 11°.

An advantage with using an abutment 1 with a short post portion 5 isthat the abutment 1 will not need being modified very often. Instead,the prosthesis may be built on the post portion 5 in its original shape.

FIG. 4 is a side view of a fourth embodiment of an abutment 1. Featurescorresponding to features of the above mentioned first embodiment ofFIGS. 1 a to 1 e have been provided with the same reference numerals asused in FIGS. 1 a to 1 e. Only the parts that differ from the firstembodiment will be described below.

The fourth embodiment differs from the first embodiment in that theextension region 11 is made very short and its outer surface 13 isforming a rather large angle φ with said longitudinal axis L.

FIGS. 5 a to 5 h depict an embodiment of a series of abutments of thetypes described in FIGS. 1 a to 4. The reference numerals in thefollowing description of FIGS. 5 a to 5 h may be referred to featuresdescribed in FIGS. 1 a to 4.

FIGS. 5 a to 5 h depicts a series of abutments wherein the angle αformed between the outer surface 8 of the post portion 5 and the outersurface 7 of the shoulder portion 8 is constant for all abutments insaid series. Further, the longitudinal extension of a component supportregion 3 is constant between all abutments in said series.

Turning to FIGS. 5 a to 5 c only, these three abutments further belongto a series in which the maximum diameter A is constant for allabutments in said series. Likewise, the three abutments of FIGS. 5 d to5 f have a common maximum diameter, and the two abutments of FIGS. 5 gto 5 h have a common maximum diameter. The abutments of FIGS. 5 a to 5 chave a maximum diameter of 4 mm, the abutments of FIGS. 5 d to f have amaximum diameter of 5 mm, and the abutments of FIGS. 5 g and 5 h have amaximum diameter of 6 mm.

FIGS. 5 a to 5 h describes a series of abutments 1 for connection of adental component to an implant, each abutment having a longitudinal axisL and comprising an implant contacting region 2, a component supportregion 3 and an extension region 11 there between 3, wherein

-   -   said extension region 11 presents an outer surface 13 forming an        angle φ with said longitudinal axis L,    -   said shoulder portion 4 presents an outer surface 7 tapering        inwardly in a coronal direction and forming an angle χ with said        longitudinal axis L,    -   said post portion 5 extending coronally from said shoulder        portion 4 and presenting an outer surface 8 tapering inwardly in        a coronal direction and forming an angle φ with said        longitudinal axis L being less than the angle χ formed by the        outer surface 7 of the shoulder portion 4 with said longitudinal        axis L, wherein,    -   said angle χ between the outer surface 7 of the shoulder portion        4 and the longitudinal axis L and said angle φ between the outer        surface 8 of the post portion 5 and the longitudinal axis L are        constant in all abutments in said series,    -   whereas the angle φ between the outer surface 13 of said        extension region 11 and said longitudinal axis L varies between        different abutments in said series.

FIG. 6 a is a perspective view of an embodiment of an abutment replica101, and FIG. 6 b is a side view of the same abutment replica 101.

The abutment replica 101 comprises a component support region 103, anextension region 111 and an apical region 102. The component supportregion 103 replicates the component support region of an abutment 1, inthis case an abutment 1 of the type depicted in FIGS. 1 a to 1 e. Thusthe component support region 103 has a shoulder portion 104 with anouter surface 107 and a post portion 105 with an outer surface 108. Inaddition, the post portion 105 includes a rotational locking means 115.

In particular, the abutment replica 101 is provided with componentengagement means 109 replicating the component engagement means 9 of theabutment 1.

Also, the abutment replica 101 is provided with a bore 130 extendingfrom an apical end of the apical portion 102 to a position coronally ofsaid component engagement means 109. In this embodiment, the bore 130 isa blind bore, but one could also consider having a bore extending allthe way through the replica 101.

The bore 130 becomes useful in situations where the abutment replica 101should be used for model making of a modified standard abutment, as isdescribed in more detail in relation to FIGS. 11 a to 11 h below.

In such situations, a coronal part of the post portion 105 is cut offthe abutment replica 101, leaving the remaining abutment replica 101with a through bore 130 extending therethrough. The through bore 130 maybe used for pouring molding material from the apical end of the replica101 for making a model of a modified abutment.

Thus, the abutment replica 101 is useful in pick-up impression making,regardless of whether standard or modified abutments are used.

The use of the marking 20 of the abutment 1 of FIGS. 1 a to 1 e, and themarking 120 on the abutment replica 101 will now be described.Preferably, there is provided a set comprising an abutment 1 having acoronal abutment end 6 and a corresponding replica 101 having a coronalreplica end 106, said abutment 1 being provided with a marking foroptional shortening of the abutment 1 at a first distance from thecoronal abutment end 6, wherein said replica 101 is provided with amarking at a second distance from the coronal replica end 106 beingequal to or slightly less than said first distance.

Such a set provides an alternative to other modification of theabutment. In case only a shortening of the abutment 1 is desired, thedental technician may shorten the abutment 1 at the marking 20. Thereplica 101 is provided with a corresponding marking 120 atapproximately the same height as the marking of the abutment 1. Thus,the dental technician need not use specific impression techniques forcapturing the modified shape of the abutment 1 when shortened, but caninstead use standard techniques only to capture the location of theabutment 1. When making a master cast model, the replica 101 isshortened to the same extent as were the abutment 1, and will thusfaithfully replicate the situation in the mouth.

Since it is difficult to cut off the abutment 1 and the replica 101exactly at the marking, the marking of the replica 101 mayadvantageously be made at a distance from the replica end 106 beingslightly less than the corresponding distance on the abutment 1. This isto provide a small margin for the dental technician when cutting of thecomponents, without risking that the abutment replica 101 turns out tobe shorter than the abutment 1.

The replica 101 and abutment 1 may each be provided with severalmarkings.

FIGS. 7 a and 7 b are perspective views of an embodiment of animpression coping for pick up impression making of a dental abutmentattached to a dental implant. FIG. 7 c is a bottom view of the sameimpression coping, FIG. 7 d is a sectional view seen from the plane I—Iin FIG. 7 a, FIG. 7 e is a sectional view seen from the plane II—II inFIG. 7 a, and FIG. 7 f is a sectional view from the plane III—III inFIG. 7 a.

The impression coping as described in FIGS. 7 a to 7 f comprises anabutment surrounding region 203 for seating on an abutment 1. Theabutment surrounding region 203 has a coronal end 206 and an apical end240, and is provided with an inner wall 207, 208.

In this embodiment, the abutment surrounding region 203 comprises ashoulder contacting portion 204 having an inner wall 207 and a postsurrounding portion 205 having an inner wall 208. The shouldercontacting portion 204 is intended to be seated on a shoulder portion ofa corresponding abutment, whereas the post surrounding portion 205 willsurround a post portion of said abutment.

On the inner wall 208 of the post surrounding portion 205, right at thetransition between the post surrounding portion 205 and the shouldercontacting portion 204, abutment engagement means 209 are provided forreleasable engagement with an abutment by linear displacement of saidimpression coping in relation to said abutment.

Said abutment engagement means 209 is provided closer to the apical end240 of the abutment contacting portion 203 than to the coronal end 206.Preferably, the distance between said apical end 240 and the abutmentengagement means 209 is less than 50%, more preferred less than 35%,most preferred less than 25% the distance between the apical end 240 andthe coronal end 206 of the abutment surrounding region 203.

As related to the shoulder contacting portion 204, a distance betweensaid shoulder contacting portion 204 and the abutment engagement means209 is preferably less than 50% the distance between the shouldercontacting portion 204 and the coronal end 206 of the abutmentsurrounding region 203, more preferred less than 30%, most preferredless than 20%.

In this embodiment, the abutment engagement means 109 comprises a ribextending around part of the inner circumference of the inner wall 208of the post surrounding portion 205. The rib is interrupted by theprovision of flat surface functioning as a rotational lock 215 extendingon the inner wall 208 of the post portion 205. It is further interruptedwhere space forming surfaces 244 are provided, said surfaces 244 beingdescribed further below.

The rib functions as a snap lock means when cooperating with acorresponding groove of an engagement means 9 on an abutment 1,realisably locking the impression coping 201 in an axial direction onthe abutment 1.

The inner wall 208 of the post contacting region 205 comprises surfaceregions having different purposes. A first surface region is an abutmentcontact surface 243 for contact with the abutment 1 when seated. Asecond surface region is a space forming surface 244, that is spacedapart from the abutment 1 when seated, forming an open space between theabutment 1 and the space forming surface 244.

The abutment contact surface 243 serves to stabilise the impressioncoping 201 when seated on an abutment 1, and to ensure that theimpression coping 201 is correctly positioned.

The space forming surface 244 serves to provide an open space betweenthe abutment 1 and the inner wall 208 of the impression coping 201. Thisis particularly useful when taking an impression of a modified standardabutment, as is described in relation to FIGS. 11 a to 11 h below.

In a transversal section of the abutment surrounding region 203, adistance r1 from a longitudinal axis L of the impression coping 201 toan abutment contact surface 243 is shorter then a distance r2 from saidlongitudinal axis L to a space forming surface 244. This distinction ispossible since abutments 1 are usually symmetrical or close tosymmetrical around a longitudinal axis, why an asymmetrical innersurface of the impression coping 201 generally means that spaces betweenthe impression coping 201 inner surface and the abutment 1 will beprovided when the impression coping 201 is attached to the abutment 1.

Put another way, the space forming surface 244 is a surface deviatingfrom an outer contour of a corresponding abutment, while the abutmentcontact surface 243 is a surface following said outer contour.

Preferably, said space forming surface 244 may be provided with a vent245 for passage of air from said space formed between the space formingsurface 244 and a corresponding abutment, when the impression coping 201is seated on said abutment. When impression material is introduced intoat least part of said space, air may flow from said space out throughthe vent 245, whereby air bubbles are avoided and proper filling of theimpression coping is ensured.

In the embodiment of FIGS. 7 a to 7 f, the vent 245 is an opening in thewall of said impression coping. The vent may also be provided by forexample a perforation.

Advantageously, the space forming surfaces 244 are extendinglongitudinally along the inner wall 208 of the post surrounding portion.As such they may form ducts for air and sometimes impression material toflow through. Vents 245 may be provided at the apical end of such ducts,being the most advantageous location for ensuring that air is let out,provided the impression material is filled from a coronal end of theimpression coping 201. Also, vents 245 may be dispersed over the spaceforming surfaces.

The wording of the terms “space forming surface” 244 and “abutmentcontact surface” 243 is related to when the impression coping 201 isseated on an unmodified abutment. However, when taking an impression ofa modified abutment, all of the abutment contact surface 243 willprobably not be in contact with the modified abutment. At least aportion of the abutment contact surface 243 will most likely not contactthe customised abutment, due to the modified shape thereof. In this casea composite space is formed between the abutment and the inner wall ofthe impression coping 201, said composite space being composed by aspace between the abutment contact surface 243 and the modified abutmentand a space between said space forming surface 244 and said modifiedabutment. Impression material may be introduced into the impressioncoping 201 and into the composite space formed between said impressioncoping 201 and the modified abutment. Thus, when removed from theabutment, the impression material together with the impression copingwill form an empty space having an inner “modified” shape correspondingto the shape of the modified abutment, said inner shape beingsubsequently used for molding a model of said modified abutment.

When the impression material is introduced into said composite space,air may flow through the space formed between said space forming surface244 and said abutment out through the vent 245, whereby air bubbles areavoided and proper filling of the impression coping is ensured. Thespace forming surface 244 thus provides an air duct for air evacuationfrom said composite space.

Naturally, the abutment may alternatively be modified such that all ofthe abutment contact surface is still in contact with the modifiedabutment, and the composite space is related only to the space formingsurfaces.

The abutment contact surfaces 243 is tapering inwardly in a coronaldirection, preferably forming an angle less than 20°, more preferredless than 15° with a longitudinal axis. In this case, said angle is 6°.Further, the abutment contact surfaces form an angle with the shouldercontacting portion 204, said angle being larger than 180°, preferably220 to 230°.

The impression coping 201 is further provided with a prolongation region241 being provided coronally of the abutment surrounding region 203. Theprolongation region 241 serves to provide a larger area for theimpression material to attach to the impression coping 201. Further, itfacilitates handling of the impression coping 201. For better retentionof the impression material, the prolongation region 241 is provided withlaterally extending retention elements 242.

The impression coping may preferably be made of a plastic material. Sucha plastic material may be selected so as to provide sufficientelasticity to allow formation of a snap lock means, but not being easilydeformable so that the stable transfer of location of an abutment duringimpression making is not impaired.

In FIGS. 8 a and 8 b an abutment 1 is shown as attached to a dentalimplant 401 implanted in bone tissue 500. An impression coping 201 isconnected to the abutment 1. Both FIG. 8 a and FIG. 8 b arecross-sectional views, FIG. 8 b being taken through the plane b—b inFIG. 8 a.

The abutment 1 is of the type described in FIGS. 1 a to 1 e, and theimpression coping 201 of the type described FIGS. 7 a to 7 f. Thereference numerals used in the descriptions of the abutment 1 and theimpression coping 201 will be used in the following, although they arenot set out in FIGS. 8 a and 8 b for lack of space.

The abutment 1 is connected to the dental implant 401 via the implantcontacting region 2 of the abutment. The threaded shaft 16 is threadedinto internal threads of a coronal bore of the implant. The coronalcontact portion 12 of the implant contacting region 2 is in sealingcontact with a conical portion of said coronal bore of the implant 401.

The extension region 11 of the abutment is extending from implantcoronal end through the gingival tissue 501. The outer diameter of theabutment is increasing from the implant contacting region 2 to a maximumdiameter A at the coronal end of the extension region 11.

The component support region 3 with the shoulder portion 4 and the postportion 5 is extending above the gingival tissue 501. The componentengagement means 9 is provided at the transition between the shoulderportion 4 and the post portion 5, thus coronally of both the maximumdiameter A of the abutment 1, and of the shoulder portion 4.

The impression coping 201 is realisably locked to the componentengagement means 9 of the abutment 1 by its own abutment engagementmeans 209. As seen in FIGS. 8 a and 8 b, the maximum diameter of theimpression coping 201 is about as large as the maximum diameter A of theabutment 1. The impression coping 201 is thus easily connectable to theabutment 1 without risk of damaging the gingival tissue surrounding theabutment. This would also be the case if the gingival tissue weresomewhat thicker, extending further coronally on the abutment.

In FIG. 8 a it is seen that the space forming surfaces 244 of theimpression coping 201 is spaced from the abutment 1. The spaces thusprovided form ducts extending from the coronal end of the throughpassage 217 of the impression coping 201 along the side of the abutmentand to the vents 245. In FIG. 8 b, the abutment contact surfaces 243 isseen to contact the abutment 1, providing support and guidance for saidimpression coping 201.

FIGS. 9 a to 9 b are perspective views of another component that may beconnected to an abutment as shown in FIGS. 1 a to 1 e. The component isan abutment carrier 301, having an apical abutment contact portion and acoronal extension portion having a ribbed outer surface to facilitategripping of the component. The abutment carrier 301 may be attached tothe abutment for facilitating handling and attachment of the abutment toan implanted fixture.

FIGS. 10 a to 10 b describes pick-up impression making and model formingwhen using a standard abutment 1.

In FIG. 10 a, two dental implants 401 are shown as implanted flush withbone tissue 500 at an implantation site between adjacent teeth.

In FIG. 10 b, it is illustrated how an abutment 1 is screwed into eachof the implants 401 using an abutment carrier 301. The abutment 1 isattached to the carrier 301 before being brought to the implantationsite. The dental surgeon initially screws the abutment 1 into theimplant 401 holding the carrier 301. Thereafter, the carrier 301 isremoved, and the abutment 1 may optionally be further tightened to theimplant 401 using a wrench.

In FIG. 10 c, it is illustrated how impression copings 201 are attachedonto the abutments 1 using the component engagement means 9 of theabutment 1 and the abutment engagement means 209 of the impressioncoping 201. Optionally, impression material may be introduced into theimpression coping 201. However, since a standard abutment 1 is used,this is not necessary.

In FIG. 10 d, impression material 600 has been applied, embedding theimpression copings 201 in the impression material 600. The impressionmaterial 600 is let to harden so as to mimic the shape of the teethadjacent the impression site and attach to the impression copings 201.

In FIG. 10 e, the impression material 600 has been removed from theimplantation site, bringing the impression copings 201 along embedded inthe material 600.

In FIG. 10 f it is depicted how standard abutment replicas 101 areintroduced into the impression copings 201 attached in the impressionmaterial. Due to engagement means and rotational locking means on theabutment replicas 101 and impression copings 201, respectively, theabutment replicas 101 are placed in the impression copings 201 in aposition corresponding to the initial position of the abutments 1 in theimpression copings 201.

In FIG. 10 g, mold material 700 has been applied to the impressionmaterial 600.

Finally, in FIG. 10 h, the impression material 600 and the impressioncopings 201 have been removed. The molding material 700 now form a modelof the implantation site with the adjacent teeth, and with the abutmentreplicas 101 corresponding to the abutments 1 at the actual implantationsite. Using this model, a proper prosthesis or crown may be manufacturedand adjusted, for later installation on the proper abutments 1 at theinstallation site.

FIGS. 11 a to 11 h describe pick-up impression making and model formingwhen using a modified abutment 1.

In FIG. 11 a, two dental implants 401 are shown as implanted flush withbone tissue 500 at an implantation site between adjacent teeth.

In FIG. 11 b, it is illustrated how abutments 1 are screwed into theimplants 401 using abutment carriers 301. The abutment 1 is attached tothe carrier 301 before being brought to the implantation site. Thedental surgeon initially screws the abutment 1 into the implant 401holding the carrier 301. Thereafter, the carrier 301 is removed, and theabutment 1 may optionally be further tightened to the implant 401 byusing a wrench.

Thereafter, the standard abutments 1 are modified for example as shownby removing a part of the coronal portion of the abutment 1. Theremaining portion is a modified abutment 1′.

In FIG. 11 c, it is illustrated how impression copings 201 are attachedonto the modified abutments 1′ using the component engagement means ofthe modified abutments 1′ and the abutment engagement means of theimpression copings 201, respectively. Since the abutments 1′ aremodified, it is necessary to introduce impression material 600′ into theimpression copings 201. The impression material 600′ may advantageouslybe introduced through the coronal end of the through passage of thecoping. When introducing impression material 600′ through the coronalend of the through passage, air may flow through the spaces formed bythe space forming surfaces 244 of the impression coping 201 and out ofthe vents 245, whereby air bubbles or inadequate filling of theimpression coping 201 is avoided. If properly introduced, the impressionmaterial 600′ together with part of the abutment contact surfaces 243 ofthe impression coping 201 will form an open space corresponding to theshape of the modified abutment 1′.

In FIG. 11 d, impression material 600 has been applied, embedding theimpression copings 201. The impression material 600 is let to harden soas to mimic the shape of the teeth adjacent the impression site andattach to the impression copings 201.

In FIG. 11 e, the impression material 600 has been removed from theimplantation site, bringing the impression copings 201 along.

In FIG. 11 f it is depicted how a coronal portion is cut off a standardabutment replica 101, so as to reveal a bore passing through theremaining part of the replica 101′. The remaining part is referred to asa cut-off replica 101′. Cut-off replicas 101′ are introduced into theimpression copings 201 embedded in the impression material usingcomponent engagement means 109. Thereafter, mold material 700′ is filledthrough the bore in the cut-off replica 101′ into the open space formedby the impression material 600′ inside the impression coping 201′ andpart of the abutment contact surfaces 243 of the impression coping 201.

In FIG. 11 g, further mold material 700 has been applied to theimpression material 600.

Finally, in FIG. 11 h, the impression material 600 and the impressioncopings 201 have been removed. The molding material 700 now forms amodel of the implantation site with the adjacent teeth. The moldingmaterial 700′ that was filled through the cut-off replicas 101′replicates the upper part of the original modified abutments 1′.However, shoulder parts of the cut-off replicas 101′ correspond to theshoulder parts of the original abutments 1 at the implantation site.

Using this model, a proper prosthesis or crown may be manufactured andadjusted, for later installation on the proper abutments 1 at theinstallation site.

It should be noted how the same abutments, impression copings andabutment replicas may be used both for the standard and the modifiedprocedure.

Other alternatives and embodiments may be considered within the scope ofthe enclosed patent claims. For example, more than one componentengagement means may be arranged on the abutment. In that case, therecould possibly be a second component engagement means being providedcoronally of the first component engagement means, although said secondcomponent engagement means may be destroyed when modifying the abutment.This could still be a functional alternative, providing said firstcomponent engagement means would provide the necessary componentcoupling function. The same applies for the abutment engagement means ofthe impression cap.

Also, the components described may possibly be consisting of two or moreinterconnected parts. However, the unitary embodiments described hereinare preferred.

The construction of engagement means and rotational locking means mayalso be varied, as may the outer shape of for example the impressioncoping, the connection to an implant of the abutment or the apicalportion of the abutment replica.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. An impression coping for pick-up impression making of a dental abutment attached to a dental implant, said impression coping having a through passage extending from a coronal end to an apical end of the impression coping, said impression coping comprising: an abutment surrounding region for surrounding the abutment, wherein said abutment surrounding region has a coronal end, an apical end and an inner wall, said inner wall comprising at least one abutment contact surface for contact with the abutment, and at least one space forming surface for being spaced apart from said abutment in order to provide a space between said space forming surface and the abutment, wherein said abutment surrounding region comprises a shoulder contacting portion having an inner wall, and a post contacting portion extending coronally from said shoulder contacting portion and presenting an inner wall forming an angle larger than 180° with said inner wall of said shoulder contacting portion, and said space forming surface and said abutment surface are provided at the inner wall of said post portion.
 2. The impression coping according to claim 1, wherein said space forming surface is provided with a vent for passage of air and/or impression material.
 3. The impression coping according to claim 1, wherein at least one abutment contact surface tapers inwardly in a coronal direction.
 4. The impression coping according to claim 3, wherein said at least one abutment contact surface forms an angle of taper of less than 20° with a longitudinal axis of said impression coping.
 5. The impression coping according to claim 4, wherein said angle of taper is less than 15°.
 6. The impression coping according to claim 4, wherein said angle of taper is 6°.
 7. The impression coping according to claim 4, wherein at least one abutment contact surface is provided with a rotational locking device, for rotational locking of said impression coping on the dental abutment.
 8. The impression coping according to claim 1, wherein said rotational locking device is formed by a flat portion of said abutment contact surface.
 9. The impression coping according to claim 1, wherein there are at least two abutment contact surfaces arranged to face each other, and two space forming surfaces arranged between said abutment contact surfaces, also facing each other.
 10. The impression coping according to claim 1, wherein a prolongation region (241) is provided coronally of said abutment surrounding region, for extension into an impression material.
 11. The impression coping according to claim 10, wherein said prolongation region is provided with retention elements for retention of the impression coping in an impression material.
 12. The impression coping according to claim 1, further comprising an abutment engagement arranged for releasable engagement with the abutment by linear displacement of said impression coping in relation to the abutment, said abutment engagement being provided apically of at least one space forming surface.
 13. The impression coping according to claim 1, further comprising an abutment engagement arranged for releasable engagement with the abutment by linear displacement of said impression coping in relation to the abutment, said abutment engagement being provided apically of at least one space forming surface, wherein said abutment engagement is provided at the post contacting portion, at a position closer to the shoulder contacting portion than to the coronal end of the abutment surrounding region.
 14. A set comprising: an abutment having a coronal abutment end; and a corresponding replica having a coronal replica end, said abutment being provided with a marking for optional shortening of the abutment at a first distance from the coronal abutment end, and wherein said replica is provided with a marking at a second distance from the coronal replica end equal to or less than said first distance.
 15. The set according to claim 14, wherein said replica and said abutment are each provided with several markings.
 16. A method for making a master cast of a modified standard abutment, comprising the steps of: providing an impression of an implant site with an impression coping embedded in impression material, and an open within said impression coping corresposnding to a modified abutment; cutting off a coronal portion of a standard abutment replica so as to obtain a remaining part of the abutment replica having a through bore extending there through; attaching said remaining part of said abutment replica to said impression coping; and pouring mold material through said through bore into the open space corresponding to the modified abutment in the impression material.
 17. A method for making a master cast of a modified standard abutment, comprising the steps of: attaching an impression coping to said modified abutment being fastened in an implant implanted in bone tissue; inserting impression material in said impression coping so as to form an open space corresponding to said modified abutment inside said impression coping; adding impression material around the site of said implant so as to embed the impression coping; removing the impression material whereby said impression coping is removed with the impression material; cutting off a coronal portion of a standard abutment replica to obtain a remaining part of the abutment replica having a through bore extending therethrough; attaching said remaining part of said abutment replica to said impression coping; pouring mold material through said through bore into the open space corresponding to the modified abutment in the impression material; and adding mold material over the entire impression material so as to create a master cast model.
 18. An impression coping for pick-up impression making of a dental abutment attached to a dental implant, said impression coping having a through passage extending from a coronal end to an apical end of the impression coping, said impression coping comprising: an abutment surrounding region for surrounding the abutment, wherein said abutment surrounding region has a coronal end, an apical end and an inner wall, said inner wall comprising at least two abutment contact surfaces for contact with the abutment, and two space forming surfaces for being spaced apart from said abutment in order to provide a space between said space forming surface and the abutment, wherein said at least two abutment contact surfaces are arranged to face each other, and said two space forming surfaces are arranged between said abutment contact surfaces, also facing each other.
 19. The impression coping according to claim 18, wherein said space forming surfaces are provided with vents for passage of air and/or impression material.
 20. The impression coping according to claim 18, wherein at least one of said at least two abutment contact surfaces tapers inwardly in a coronal direction.
 21. The impression coping according to claim 20, wherein at least one of said at least two abutment contact surfaces forms an angle of taper of less than 20° with a longitudinal axis of said impression coping.
 22. The impression coping according to claim 21, wherein said angle of taper is less than 15°.
 23. The impression coping according to claim 21, wherein said angle of taper is 6°.
 24. The impression coping according to claim 18, wherein at least one of said at least two abutment contact surfaces is provided with a rotational locking device, for rotational locking of said impression coping on the dental abutment.
 25. The impression coping according to claim 24, wherein said rotational locking device is formed by a flat portion of said abutment contact surface.
 26. The impression coping according to claim 18, wherein a prolongation region is provided coronally of said abutment surrounding region, for extension into an impression material.
 27. The impression coping according to claim 18, wherein said prolongation region is provided with retention elements for retention of the impression coping in an impression material.
 28. The impression coping according to claim 18, further comprising an abutment engagement arranged for releasable engagement with the abutment by linear displacement of said impression coping in relation to the abutment, said abutment engagement being provided apically of at least one of said two space forming surfaces.
 29. The impression coping according to claim 28, wherein said abutment engagement is provided at a post contacting portion, at a position closer to the shoulder contacting portion than to the coronal end of the abutment surrounding region. 